On a cold winter day, the outside temperature is -20°C and the inside temperature is maintained at 20°C. There is a net heat flow to the outside through the walls, roof, etc., of 25 kW. What is the rate of increase of the entropy of the universe as a result of this heat flow?
Okay,
so
S_{hot} = 25000 / 293 = 85.3 W/K
S_{cold} = 25000 / 253 = 98.8 W/K
Therefore,
rate of increase of the entropy of the universe
S = 98.8 - 85.3
S = 13 W/K
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